The market for metal containers has developed widely in recent years due in part to the introduction of the easy open end. While the easy opening feature has been shown to be both effective and convenient, it has given rise to a collateral problem of littering, since traditionally the easy opening feature was pulled free from the container to expose the contents and then subsequently discarded. The indiscriminate disposal of the pull tabs is not only unsightly, but can also present a safety hazard particulary on beaches and in parks.
A number of solutions to the problem have been developed by the container industry with one of the more successful being the retained lever tab. In this structure, the tab is joined to the container end by a tongue or flap which serves as a tab retaining strip after the container has been opened. Since the tab operates as a lever, it must be sufficiently rigid to preclude buckling during the opening process. The rigidity is typically developed in the tab by curling the edges of the tab and also by utilizing tab stock of relatively heavy gage typically 0.018" in thickness. The tongue, which is the bendable member of the tab, when fabricated of such heavy stock, is prone to fracture when subjected to severe bending, as may be encountered when it is bent forward to open the end and then subsequently bent backward to fold the tab out of the way. The situation is further aggravated by the user's inclination to worry the tab by bending it back and forth in an effort to free it from the container in keeping with past practice.
In U.S. Pat. No. 3,967,752 and U.S. Pat. No. 3,967,753 a fracture resistant tongue tab is disclosed wherein a sub-tab of plastic or ductile aluminum is interleafed into the folds of the tab nose to provide a flexible and fracture resistant linkage between the tab and the end. While this composite structure improves the fracture resistance of the tab, it requires additional material and press time for fabrication.
Tear through of the tab tongue, wherein the tongue is extended by tearing of the web, is an additional problem with lever tabs. This condition, which is most apt to arise when score residuals are high, results in a tab which remains attached to the end, but is inoperative.
Accordingly, it is an objective of the instant invention to provide a noval lever type opening feature for easy open containers, which is effective and overcomes the problem of the tab litter.
It is more particularly an objective of the instant invention to provide a lever type tongue tab for easy open containers, which is resistant to both fracture and tear.
Finally, it is an objective of the instant invention to provide a lever style tongue tab, which is simple, highly effective and of inexpensive construction.